Changeset 969 for trunk/src/corelib/io/qprocess_os2.cpp

Timestamp:

Aug 11, 2011, 10:57:43 PM (14 years ago)

Author:

Dmitry A. Kuminov

Message:

OS/2: QProcess: Fix hangs when using sync funcs in a GUI program.

An extra asynchronous notification could lead to the same payload being
read from the pipe twice leading to a blocking DosRead call.

File:

• trunk/src/corelib/io/qprocess_os2.cpp (modified) (4 diffs)

trunk/src/corelib/io/qprocess_os2.cpp

@@ -1259 +1259 @@
 }
 
-qint64 QProcessPrivate::bytesAvailableFromStdout() const
-{
-    if (!dying && pipeData[OutPipe].signaled) {
-        // reuse the number we stored in _q_notified()
-        DEBUG(("QProcessPrivate::bytesAvailableFromStdout() == %lld (reused)",
-               pipeData[OutPipe].bytes));
-        return pipeData[OutPipe].bytes;
-    }
-
+// static
+qint64 QProcessPrivate::bytesAvailableFromPipe(HPIPE hpipe, bool *closed)
+{
     qint64 bytes = 0;
-    if (stdoutChannel.pipe.server != HPIPE(~0) &&
-        (!dying || stdoutChannel.type == QProcessPrivate::Channel::Normal)) {
+    if (hpipe != HPIPE(~0)) {
         ULONG state, dummy;
         AVAILDATA avail;
-        APIRET arc = DosPeekNPipe(stdoutChannel.pipe.server, 0, 0, &dummy,
-                                  &avail, &state);
+        APIRET arc = DosPeekNPipe(hpipe, 0, 0, &dummy, &avail, &state);
         Q_ASSERT(arc == NO_ERROR);
         Q_UNUSED(arc);
         bytes = (qint64)avail.cbpipe;
-        if (!dying && state != NP_STATE_CONNECTED) {
-            // if the pipe is closed, we negate the result (to preserve the
-            // number of bytes remaining) and add -1 to it (to distinguish from
-            // the case when there's no data byt the pipe is not closed)
-            bytes = -1 - bytes;
-        }
+        if (closed) {
+            *closed = state != NP_STATE_CONNECTED;
+        }
+    }
+    return bytes;
+}
+
+qint64 QProcessPrivate::bytesAvailableFromStdout() const
+{
+    qint64 bytes = 0;
+    if (!dying) {
+        Q_ASSERT(pipeData[OutPipe].signaled);
+        // reuse the number we got in _q_notified()
+        bytes = pipeData[OutPipe].bytes;
+    } else {
+        if (stdoutChannel.type == QProcessPrivate::Channel::Normal)
+            bytes = bytesAvailableFromPipe(stdoutChannel.pipe.server);
     }
 
@@ -1292 +1295 @@
 qint64 QProcessPrivate::bytesAvailableFromStderr() const
 {
-    if (!dying && pipeData[ErrPipe].signaled) {
-        // reuse the number we stored in _q_notified()
-        DEBUG(("QProcessPrivate::bytesAvailableFromStderr() == %lld (reused)",
-               pipeData[ErrPipe].bytes));
-        return pipeData[ErrPipe].bytes;
-    }
-
     qint64 bytes = 0;
-    if (stderrChannel.pipe.server != HPIPE(~0) &&
-        (!dying || stderrChannel.type == QProcessPrivate::Channel::Normal)) {
-        ULONG state, dummy;
-        AVAILDATA avail;
-        APIRET arc = DosPeekNPipe(stderrChannel.pipe.server, 0, 0, &dummy,
-                                  &avail, &state);
-        Q_ASSERT(arc == NO_ERROR);
-        Q_UNUSED(arc);
-        bytes = (qint64)avail.cbpipe;
-        if (!dying && state != NP_STATE_CONNECTED) {
-            // if the pipe is closed, we negate the result (to preserve the
-            // number of bytes remaining) and add -1 to it (to distinguish from
-            // the case when there's no data byt the pipe is not closed)
-            bytes = -1 - bytes;
-        }
+    if (!dying) {
+        Q_ASSERT(pipeData[ErrPipe].signaled);
+        // reuse the number we got in _q_notified()
+        bytes = pipeData[ErrPipe].bytes;
+    } else {
+        if (stderrChannel.type == QProcessPrivate::Channel::Normal)
+            bytes = bytesAvailableFromPipe(stderrChannel.pipe.server);
     }
 
@@ -1657 +1645 @@
     // the remote end of the pipe indicated by bytes < 0
 
+
+
+
+
+
     if (flags & CanReadStdOut) {
-        qint64 bytes = bytesAvailableFromStdout();
-        if (bytes) {
-            bool closed = false;
-            if (bytes < 0) {
-                bytes = -1 -bytes;
-                closed = true;
-            }
+        Q_ASSERT(!pipeData[OutPipe].signaled || waitMode);
+        bool closed = false;
+        qint64 bytes = bytesAvailableFromPipe(stdoutChannel.pipe.server, &closed);
+        if (bytes || closed) {
             pipeData[OutPipe].bytes = bytes;
             pipeData[OutPipe].signaled = true;
@@ -1686 +1676 @@
 
     if (flags & CanReadStdErr) {
-        qint64 bytes = bytesAvailableFromStderr();
-        if (bytes) {
-            bool closed = false;
-            if (bytes < 0) {
-                bytes = -1 -bytes;
-                closed = true;
-            }
+        Q_ASSERT(!pipeData[ErrPipe].signaled || waitMode);
+        bool closed = false;
+        qint64 bytes = bytesAvailableFromPipe(stderrChannel.pipe.server, &closed);
+        if (bytes || closed) {
             pipeData[ErrPipe].bytes = bytes;
             pipeData[ErrPipe].signaled = true;